First China targeted Facebook and Twitter – now it's going after the world's largest e-mail service. The targeting of Gmail is part of a broader ideological struggle to separate the Middle Kingdom from the modes of the West.

In this March 23, 2010 file photo, a security guard walks past while foreign visitors are seen inside the Google China headquarters in Beijing. Connections to Google Inc.'s popular email service have been blocked in China amid efforts by the government to limit access to the company's services.

Beijing — China has cemented another brick into the Great Firewall of censorship that blocks its citizens’ access to large swaths of the Internet, sealing off Google’s Gmail service.

Google traffic in and out of China plummeted on Dec. 26 and has flatlined since, according to Google’s records.

“We’ve checked and there is no problem at our end,” said Taj Meadows, Google spokesman for Asia. The Chinese Ministry of Information and Technology, responsible for the technical aspects of Internet censorship, did not reply to faxed questions.

The abrupt halt in services left millions of Chinese Gmail users stranded. Among them was Song Ming, a furniture trader in Bengbu in the southern province of Anhui, who suddenly found himself cut off from his customers. “I had no time to inform my clients,” he said. “If Gmail has problems … it is too risky to keep using it.”

Also angered by the censors’ move was a travel agent in the western city of Xian. “This really affects my business very much,” he said asking not to be identified for fear of official retribution. “I’d switched to Gmail because I thought it was worldwide.”

It had been getting harder and harder to use Google products such as Gmail, Search, and Google Docs since the summer. Now only special Virtual Private Network software, which circumvents the censor, gives access to those services in China.

Gmail does not have a huge number of users here. The service enjoys less than 2 percent of the Chinese e-mail market, according to a study by Internet traffic analyst Hitwise reported last year.

But the new block is symptomatic of the Chinese authorities’ attitude to the Internet. “This is not a major blow to the business, but it is a further tightening of the screw,” said one source familiar with the situation who asked not to be identified because he was not authorized to speak on the record.

“It is as if they have decided Google is the enemy, it is really grim,” added Jeremy Goldkorn, an Internet entrepreneur in Beijing.

It is clear that the Chinese government led by President Xi Jinping sees the Internet as a key battlefield in its ideological struggle with the West.

“The Internet has become the main battlefield in the struggle for public opinion,” President Xi told fellow leaders at a meeting to discuss ideology in August last year. “On this battlefield of the Internet, whether we can stand up and gain victory relates directly to our country’s ideological security and regime security.”

Beijing’s strategy depends on shutting China off from the rest of the world’s Internet when it is seen as a threat to the government.

“I can choose who will be a guest in my home,” said Lu Wei, the government’s top Internet regulator last month, justifying blocks on such websites as Facebook, Twitter, and Instagram.

At an international Internet conference in November held in the southern city of Wuzhen, Chinese organizers promoted a statement calling on nations to “respect Internet sovereignty of all countries."

This was seen as a bid to block international criticism of the Chinese government’s strict web censorship. The statement was eventually withdrawn; conference participants said it had been clumsily presented with no opportunity for debate.

But with or without international approval, Beijing is clearly determined to build China’s Internet according to its own model, said a businessman in the industry.

“China is a country with its own rules and if you want to do business here, you have to abide by them,” said Lawrence Sheed, founder of a company that hosts websites and mail service in China. “They want to control the information. If they cannot approve it, if it is not under their control, it is not allowed."